What magnitude of benefit is meaningful to cancer patients?

Oncologists often use the phrase “clinically meaningful benefit” to describe the effect of an experimental treatment. But is the benefit meaningful for patients? A new paper suggests that benefit claims in journal articles often fall short.

They compared the outcome of each trial with the thresholds of clinically meaningful benefit proposed by the American Society of Clinical Oncology and the European Society of Medical Oncology. (In terms of overall survival, for example, the ASCO guidelines suggest that new drugs should result in a relative increase in median overall survival of at least 20 percent, or 2.5 to 6 months.)

Claims of a “clinically meaningful” benefit based on overall survival did not meet the ASCO and ESMO guidelines 60 to 70 percent of the time. Claims based on progression-free survival did not stack up 30 percent of the time.

“Given that the ASCO and ESMO thresholds are modest, we believe real world usage that falls short of this is setting the bar too low for our patients,” concluded Dreicer, Prasad and co-authors. “Future research should explore what magnitudes of benefit patients consider meaningful benefit, and whether these might serve as an externally valid metric for professional societies.”

Claims of a “clinically meaningful” survival benefit did not meet ASCO and ESMO guidelines 60 to 70 percent of the time.

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Part of the problem is the increasing pervasiveness of clinical trials designed to detect effect sizes that are too small to be clinically meaningful. In a review of 226 randomized clinical trials of systemic cancer therapies, researchers found that less than a third were designed to detect or exclude a difference between treatment arms that could meet ESMO criteria for meaningful clinical benefit.

Overstating the benefits of a new cancer therapy is no trivial matter. It undermines the credibility of journals. It confuses decisions about how to allocate funding for medical care. And it harms patients who pursue treatments based on exaggerated expectations of benefit without a realistic understanding of the risk of adverse effects and the personal financial toll.

About the author

Joe Rojas-Burke

I worked as a cell biology researcher at the Rockefeller University in New York City until I figured out that I could make a living writing about science for newspapers and magazines. I've been a science writer with the OHSU Knight Cancer Institute since September 2015.

About Cancer Translated

Brought to you by the OHSU Knight Cancer Institute, this blog explores new findings, ideas and debates in cancer research and treatment – from basic biology and clinical trials to prevention and survivorship.